Generally via wrapping (Composition).
``` struct Foo <: AbstractFoo ... end
struct SpecialFoo{T<:AbstractFoo} <: AbstractFoo backing::T end ```
and then delegating calls to the wrapped object
``` struct Foo <: AbstractFoo ... end
struct SpecialFoo{T<:AbstractFoo} <: AbstractFoo backing::T end ```
and then delegating calls to the wrapped object
[1] https://github.com/MikeInnes/Lazy.jl/blob/0de1643f37555396d6...
I have seen many and alway immediately run into cases they can't handle.
A top level `for m in (:foo, :bar); @eval $m(X::MyType) = $m(X.backing)`
Is general and has no performance overhead
The nice thing about the Julia ecosystem is that people tend to be pretty willing to step back and define their methods in terms of an interface (Tables.jl in this case) which then allows code reuse without brittle delegation. Having to put so much effort into changing the structure of upstream doesn't seem ideal from a composability perspective though.